/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.tsfile.common.bitStream;

import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;

public class ByteBufferBackedInputStream extends InputStream {
  private final ByteBuffer buf;
  private final int startPos;

  public ByteBufferBackedInputStream(ByteBuffer buf) {
    this.buf = buf;
    this.startPos = buf.position();
  }

  @Override
  public int read() throws IOException {
    if (!buf.hasRemaining()) {
      return -1;
    }
    return buf.get() & 0xFF;
  }

  @Override
  public int available() {
    return buf.remaining();
  }

  public int getConsumed() {
    return buf.position() - startPos;
  }
}
